Ac solenoid on thermoquad

I'm with 67Dart273. I suspect the ebay seller ASSumed the solenoid was to increase idle speed when the AC compressor turns on. But, I don't recall those being used in U.S. cars until 4 cyl engines of the early 1980's when the AC turning on greatly affected idle speed. They might have transitioned them to 6 and 8 cyl engine later. Indeed, they even had to change to more efficient rotary AC compressors then too.